Lens-measuring instrument.



F. HARDINGE. LENS MEASURING INSTRUMENT.

APPLICATION I'ILED NO\T.17, 190 RENEWED AUG. 22, 1908.

Patented Oct. 6; 1903.

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*Zddtnexes I @TATES rarnnr cr mes.

FRANKLIN HARDING-l OF CHICAGO, ILLINOIS, ASSIGNOR TO GENEVA OPTICAL COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION.

LENS-MEASURING INSTRUMENT.

Specification of Letters Patent.

Patented 0a. e, 1903.

Application filed November 17, 19Q6, Serial No. 343,791. Renewed August-22, 1908. Serial No. 9,822.

To all whom it may concern:

Be it known that L'FRANKLIN HARDINGE, citizen of the United States, residing at Chicage, in the county of Cook and State of Illinois, have invented a certain new and useful improvement in Lens Measuring Instruments, of which. the following is a full, clear, concise, and exact description, rcfcrcncebeing had to the accompanying drawings, forming a part of this specification.

My invention relates to lens measuring instruments and may be considered as an improvement over the lens measuring instrument disclosed in my Patent No. 703,725

fore, is to provide multiplying lever mech ainsm and arrangement thereof so that the.

measuring points may be brought closer together to adapt the instrument for measuring small lenses or small pieces of broken lens, the improved lever arrangement being such that the distance vapart of the dial marks and the throw of the needle will be increased in spite of the fact that the points are brought closertogether and, therefore, enabling the indication to be read with much greater accuracy.

With the exception of my improved lever mechanism, the device is practically of the 'same construction as that shown in the patrent, and in the accompanying drawing1 igure 1 1s a face View of the mstrument, show- F ing the measuring points and needle in their normal position and showing in dotted lines the position assumed when the points are in the same plane; Fig. 2 is an enlarged face view, the crystal, frame, needle and-dial being removed, and the pointsupporting frame being in section, and Fig. '3 is a sectional View taken on line 3-3 of Fig. 2. p

The casing A is provided with a bezel B in which is set a crystal C. The graduated dial 1) is secured to the edge of the casing A by the bezel B, and E is the pointer movable over the face of the "dial. At the bottom of the casing A is the; supporting plate F on which the various moving parts are mounted. Secured to the upper end of this supporting plate and extending through the casing walls is the pin supporting block G in which are mounted the movable measuring pin or point H and the comparatively immovable pins or points H and H The pin H is adapted to slide readily in its channel a, while the pins H and H? are held in adjusted position by their frictional engagement with the walls of their compartments 4) and 10 respectively,

. the lower ends of these compartments being pinion" K and thohair spring L, which v pinion and hair spring are mountedon the spindle M at whose outer end is supported the needle E. The free end of the hair spring is secured to the lug N which is in tegral with the part J. To hold the lower P is a bent 11111 pivoted at its lower end to the plate F by the sercw'd,being pivoted at 1ts-upper end at (Z' to the lever arm Q whose front end q is hook-shaped, as shown,

the end thereof being beveled and-rounded to term the contact point 1 which engages in the channel a cut-in the head of the trio-- tion nut I. Between the ends of the lover I" is the slot 1) through which engages the screw- 0 by means of which the lover I may be secured in any adjusted position. At the left side of the casing is the pivot frame R pivoted to the frame F by the screw f. At

the upper end ofthis pivot frame is the slot g through which passes the screw it into engagement with the platc l ,'the slot allowing ad uStment of the lever frame about its pivot 'cnd of the frame in place, a lockingplate O and the screw serving to secure the frame in any adjusted position. Pivoted at the point j to the frame It is the lever arm S termi nating at its right end in the segmental rack s engaging with the needle pinion K. A

tension spring is extending between the fixed pin land the hook arm m extending from the lever arm S tends to hold the arm and segmental rack in an upper position. Also extending from the arm S between the pivot point j and segmental rack is an extending arm n from which extends forwardly the pin 0 terminating in the retaining flange 7).

Another lever arm T is pivoted tothe frame F at t suitably placed below the lever Q. The lever arm T is bent, as shown, to clear the bent end of the lever Q, and the end of this lever T engages the pin -0 between the arm end it and the flange 79'. A pivot point or lug 2? extends forwardly from the lever arm T between the pivot point t and the end of this arm so that it will. engage the underside, of the lever arm Q, at about its middle .point. With this iarrangement of levers, it

will be seen that the inward movement of the measuring pin H will be'transmitted tion, this return movement of the needle being..assisted by the hair spring L, this hair spring serving also to take up all backlash between the segment rack and the needle pinion. I

v "The dial may be graduated in any suit-able manner, but is preferably uniformly gratin-- ated, as is shown in Fig. 1. The lever sup porting frames may be so adjusted that .when the points are brought against a plain .surface, the needle will indicate zero. If a convex lens or surface is to be measured, the pointer will be moved to the plus (-1-) side of the dial, whereas if the points are brought against a concave lens or surface,

. through which the point 7' is moved on either the needlewill indicate on the minus side in the'manner well understood in the art, and the proper adjustment for the levers is determined by testing the instrument with lenses or surfaces of known curvature. In this present device as in the device in the patent referred to, the center of the pivotd, the pivot points If and r, the

top edge of the pin 0 and the pivot j will be 1 in the same horizontal plane when the measuring pin points are in the same plane, and therefore, the lever movements at either side of the zero. position are practically in a straight line, and the successive intervals side of thisline of centers by convex and concave surfaces are uniform and are d irectly proportional to the variations in curvature, and this particular arrangement allows the use of the uniformly graduated scale. The particular arrangement of the levers, pivots and contacts also compensates for the ditference'in focal length of convex the concave lenses. This is brought about by the fact that the levers S and T are arranged at an angle with each other, as shown, theleverage of the arm T becoming greater as the arm S is moved rearwardly, or in other words, the pin 0 moves below the line of centers. This causes the pointer or needle E to be moved through an arc to the left by a convex lens slightly greater than the are through which it will be moved to the right by a concave lens of the same radius of curvature. By this arrangement, therefore, convex and concave surfaces of the same radius of curvature but with different focal length will be accurately measured on a uniformly divided scale.

By the interposition of the additional lever arm Q, instead of directly connecting the lever arm T with the pin 0, as is the case in the patent, the deflection of the icedle corresponding to any movement 0 the levers, may be greatly multiplied to any extent to allow the use of larger scale divisions and more close spacing of the measuring pins, adapting the device to the measurement of very small lenses or pieces of broken lenses. This multiplication is evident from the use of the interposed lever arm Q, and the position of the point 6 close to the pivot point i; of the lever arm T.

In assembling the instrun'ient, the lever supporting frames are approximately adjusted to produce correct readings, and the dial pointer and crystal are then put in place. To get absolutely correct adjustment, it is necessary only to turn the movable measuring pin H in the spring nut, thereby adjusting the point of the middle pin with respect to the outside pins. \Vhen the dcvice is, therefore, assembled, it is unnecessary for the user to take it apart to obtain an exact adjustment, but this adjustment can be readily accomplished by the mere turning of the movable measuring pin, and the wear of the pins can be compensated for in the same manner. I

I do notwish to be limited to this precise arrangement of the various supporting parts or the multiplying levers, as'changes may readily be made without departing from the scope of the invention,- the main feature being the proper arrangement of a sufiicient number of multiplying levers, so that the scale divisions may be of suflicient size and measuring. points brought sufiicientl close together to enable measurement 0 small lenses without in any way deducting from the efiiciency or accuracy of the readings or measurements.

I claim as new and desireto secure by Letters atent: i

1. .w n a measuring instrument of'the class described, the combination of relatively fixed contact members, a movable contact member, an indicating pointer, a lever pivoted at one end and engaging at its other end with the movable contact member, a sec nd lever pivoted at one end and having diving connectlon at its other end with the pointer, and a third lever pivoted at one end, the other end of the lever engaging the second'lever at an, intermediary point thereof and said third lever engaging an intermediary point of the first lever. 1

2. In a measuring instrument of the class described, the comblnation ofcomparatively :fixed measuring contact members, a relac'p'ntact member,

tively' movable measurin' an indicating pointer, an -multiplying lever mechanism comprising three, pivotedlevers the first lever having contact with the second lever and the second lever having contact with the third lever, such levers belng so arranged that the pivot centers of two of the levers and thecontact points thereoflie in a straight horizontal line when the points of the contact members are in a horizontal plane.

3. In a measuring instrument of the class described, the combination of comparatively fixed measuring contact members, arela-. tlvely movable measurlng contact member,

an indicatin pointer a lever pivoted to the instrument rame and havmg direct connec-' tion with the movable member, a secondlever-pivoted to the instrument frame and having driving connection with the pointer, and a third lever pivoted to the instrument frame and having. contact engagement with the fi-rstand'second levers,the pivot centers of the firstand second levers and the en.-

gagement contact points between said leversand the third lever lying afl i th horizontal plane when the points of the horizontal plane. 1 7' I 4. .In a measuring instrument of'theclass described, thecombination of fixed measuring contact, members, a relativelymovable v 5 measuring contact members lie all 1n another measuring contact member, an indicatings I pointer, .a. pivoted lever havingdirectconta'ct'with the movable member, a second pivoted lever having direct. driving connection "with the pointer, and additional lever mechanism having contact eng 7 afement, with the first and second levers or transferring movement 'from' one of said levers tothe pointer, and multiplying lever mechanism comprising 7 lever havln contact with the second. and

mg contact members, a relatively movable measuring contact member, an indicatlng' three pivoted lovers the first theseoond ever having contact with the third lever, said levers being so arranged that the "pivot centers of two of the levers and the contact points of all the levers lie in a straight horizontal line when the points of :the. contact members are in .a horizontalq plane.

- p In witness whereof, I hereunto subscribe lilly name this 14th day of November A. D., Y l FRANKLIN HARDINGE.

Witnesses CHARLES J. SCHMIDT,

'- GEORGE E. HIGHAM. 

